JP5697042B2 - System for increasing gene expression and vector carrying the system - Google Patents

Description

  The present invention relates to a method for increasing gene expression using a promoter, an enhancer or the like, and an expression cassette for increasing gene expression including a promoter, an enhancer or the like.

Various gene expression promoters such as CMV promoter and CAG promoter have been developed in order to increase gene expression efficiency (Patent Documents 1 to 4). However, in the field of biotechnology, even if these conventional techniques are used, problems such as almost no gene expression or a very small amount of expressed protein occur on a daily basis, depending on the cell type and gene type. . This problem is also a major barrier in the development of medicine that uses gene expression for diagnosis and treatment.
Japanese Patent No. 2814433 Japanese Patent No. 2814434 US Pat. No. 5,168,062 US Pat. No. 5,385,839

It is an object of the present invention to provide a method for increasing gene expression using a promoter, enhancer or the like, and an expression cassette capable of increasing gene expression including a promoter, enhancer or the like.
The present inventor attempted to develop a new system capable of expressing a gene with higher efficiency in a gene expression system using a promoter, and compared and examined promoter activities by a combination of promoters and enhancers of various genes. It was. As a result, the gene to be expressed downstream of the first promoter and the DNA construct containing the poly A addition sequence are expressed using a gene expression cassette in which an enhancer or a second promoter is connected downstream of the DNA construct. It was found that the gene can be expressed with high efficiency by sandwiching the gene to be sandwiched between two promoters or a promoter and an enhancer. The present inventor further found that the gene can be expressed with higher efficiency by further including elements such as polyA additional sequence, RU5 ′, UAS, and SV40-ori in the expression cassette.
With the development of the “system for increasing gene expression and a vector retaining the system” of the present invention, protein expression can be strongly increased for almost all cells and genes.
That is, the present invention is as follows.
[1] A gene expression cassette comprising a DNA construct comprising a gene to be expressed downstream of a first promoter and a poly A addition sequence, and further comprising an enhancer or a second promoter downstream of the DNA construct.
[2] There is no other gene expression mechanism downstream of the linked enhancer or the second promoter, and the gene to be expressed is sandwiched between one first promoter and one enhancer, or the first The expression cassette according to [1], which has a structure sandwiched between one promoter and one second promoter.
[3] The expression cassette according to [1], wherein the promoter is a promoter selected from the group consisting of CMV i promoter, SV40 promoter, hTERT promoter, β-actin promoter and CAG promoter.
[4] The expression cassette according to any one of [1] to [3], wherein the enhancer is at least one enhancer selected from the group consisting of a CMV enhancer, an SV40 enhancer, and an hTERT enhancer.
[5] Furthermore, 1 to 4 CMV enhancers are linked upstream of a DNA construct containing DNA encoding a protein to be expressed downstream of the promoter and a poly A addition sequence. Any expression cassette.
[6] The expression cassette according to any one of [1] to [5], further comprising at least one of the following elements:
(I) RU5 ′ linked immediately upstream of the DNA encoding the foreign protein;
(Ii) UAS linked immediately upstream of the enhancer and / or promoter; and (iii) SV40-ori linked to the uppermost stream of the expression cassette.
[7] The expression cassette according to any one of [1] to [6], wherein the gene to be expressed is a therapeutic gene that can be used for treatment of a disease, or a protein gene that can be used for a medicine, a diagnostic agent, or a reagent. .
[8] The expression cassette according to [7], wherein the therapeutic gene is a tumor suppressor gene that can be used for tumor therapy.
[9] The expression cassette of [8], wherein the tumor suppressor gene is a REIC / Dkk-3 gene.
[10] The expression cassette according to [9], wherein the gene to be expressed is a fragment DNA of the REIC / Dkk-3 gene.
[11] The expression cassette according to [10], wherein the fragment DNA of the REIC / Dkk-3 gene is DNA encoding amino acids 1 to 78 of the amino acid sequence of SEQ ID NO: 18.
[12] Construct No. 2 (FIG. 8), no. 4 (FIG. 10), no. 6 (FIG. 12), no. 8 (FIG. 14), no. 10 (FIG. 16), no. 12 (FIG. 18) and The cassette for expression of the foreign gene of [1] which has the structure shown in FIG. 14 (FIG. 20).
[13] Construct No. 15 (FIG. 16), no. 16 (FIG. 37), no. 17 (FIG. 49), no. 20 (FIG. 57) and no. The cassette for expression of the foreign gene of [1] which has a structure shown in FIG. 21 (FIG. 58).
[14] A vector comprising a cassette for expression of a foreign gene according to any one of [1] to [13].
[15] The vector according to [14], which is an adenovirus or an adeno-associated virus vector.
[16] A host cell comprising the vector of [14] or [15].
[17] A disease detection or treatment preparation comprising the vector of [14] or [15].
[18] A method for expressing a gene to be expressed using the expression cassette according to any one of [1] to [13] or the vector according to [14] or [15].
[19] A DNA construct containing a gene to be expressed and a poly A addition sequence downstream of the first promoter and an enhancer or second promoter linked to the DNA construct are introduced into a vector, and the vector is used. To express the gene.
[20] An expression cassette comprising introducing the expression cassette according to any one of [1] to [13] or the vector according to [14] or [15] into a cell and culturing the cell. A method for producing a protein encoded by a gene to be encoded.
This specification includes the contents described in the specification and / or drawings of Japanese Patent Application No. 2009-264299 which is the basis of the priority of the present application.

FIG. 1 shows the expression of various foreign genes transfected into HEK293 cell line using FuGENE ™ -HD for 36 hours.
FIG. 2 shows the expression of KLF gene transfected into various cell lines using FuGENE ™ -HD for 36 hours.
FIG. 3 shows the expression of KLF gene transfected into HEK293 cell line for 36 hours using various transfection reagents.
FIG. 4 is a diagram showing the expression when the HEK293 cell line was transfected with a gene encoding full-length REIC gene and N78-REIC for 36 hours using FuGENE ™ -HD.
FIG. 5A shows a construct No. in which DNA encoding N78-REIC was inserted. 14 is a graph (graph) showing growth suppression and cell death induction of human prostate cancer cell PC3 cell line according to FIG.
FIG. 5-2 shows construct No. 5 inserted with DNA encoding N78-REIC. FIG. 14 is a diagram (photograph) showing growth suppression and cell death induction of human prostate cancer cell PC3 cell line according to FIG.
FIG. 6 shows construct No. in which full-length REIC gene was inserted. FIG. 14 shows growth inhibition of human prostate cancer cell PC3 cell line according to FIG.
FIG. FIG.
FIG. It is a figure which shows the structure of 2.
FIG. FIG.
FIG. FIG.
FIG. FIG.
FIG. 6 is a diagram showing the structure of FIG.
FIG. FIG.
FIG. FIG.
FIG. FIG.
FIG. FIG.
FIG. FIG.
FIG. 18 shows the structure No. It is a figure which shows the structure of 12.
FIG. 19 shows the structure No. It is a figure which shows the structure of 13.
FIG. 20 shows the structure No. FIG.
FIG. 21 is a diagram showing the structure of an adenovirus construct encoding the full-length REIC / Dkk-3 gene.
FIG. 22-1 is a diagram showing the entire base sequence of pDNR-1r Donor vector.
FIG. 22-2 is a diagram showing the entire base sequence of pDNR-1r Donor vector (continuation of FIG. 22-1).
FIG. 23 is a diagram showing the entire base sequence of the pIDT-SMART vector.
FIG. 24 is a diagram showing the base sequence of the CMV i promoter (hCMV + intron promoter) region.
FIG. 25 is a diagram showing the base sequence of the BGH polyA (3 × stop + BGH polyA) region.
FIG. 26 is a diagram showing the base sequence of the CMV enhancer region.
FIG. 27 shows the nucleotide sequence of the human β-actin promoter region.
FIG. 28 is a diagram showing the base sequence of the RU5 ′ forward direction {HTLV Type 1 long terminal repeat R segment and part of the U5 sequence (R-U5 ′)} region.
FIG. 29 is a diagram showing the base sequence of the RU5 ′ reverse direction {HTLV Type 1 long terminal repeat R segment and part of the U5 sequence (R-U5 ′)} region.
FIG. 30 is a diagram showing the base sequence of the 4 × CMV enhancer region.
FIG. 31 shows the base sequence of the CAG promoter region.
FIG. 32 shows the base sequence of the 2IRES insert region.
FIG. 33 shows the nucleotide sequence of the SV40ori-UAS-CMVi-RU5 ′ region.
FIG. 34 is a diagram showing the base sequence of 3 × stop-BGH-polyA-UAS-hTERT enhancer + SV40 enhancer + CMV enhancer region.
FIG. It is a figure which shows the whole base sequence of 14 vectors.
FIG. It is a figure which shows the whole base sequence of 14 vectors (continuation of FIG. 35-1).
FIG. 36 shows the structure No. FIG.
FIG. FIG.
FIG. 38 is a diagram showing the nucleotide sequence of the SV40ori-UAS-SV40 enh-intron A-RU 5 ′ region. It is a figure which shows the base sequence of the insertion part of the left side (upstream side) from 15 insertion genes (target gene).
FIG. 39 is a diagram showing the base sequence of the SV40ori-UAS-hTERT enh-intron A-RU 5 ′ region. It is a figure which shows the base sequence of the insertion part of the left side (upstream side) from 16 insertion genes (target gene).
FIG. 40 shows the nucleotide sequence of the GFP region in the plasmid.
FIG. It is a figure which shows the base sequence of the plasmid which inserted DNA of the GFP gene in 14 insertion gene (target gene) area | regions.
FIG. 41-2 shows the structure No. It is a figure which shows the base sequence of the plasmid which inserted DNA of the GFP gene in 14 insertion gene (target gene) area | regions (continuation of FIG. 41-1).
FIG. 42-1 shows the structure No. It is a figure which shows the base sequence of the plasmid which inserted DNA of the GFP gene in 15 insertion gene (target gene) area | regions.
FIG. 42-2 shows construct no. It is a figure which shows the base sequence of the plasmid which inserted DNA of the GFP gene in 15 insertion gene (target gene) area | regions (continuation of FIG. 42-1).
FIG. It is a figure which shows the base sequence of the plasmid which inserted DNA of the GFP gene in 16 insertion gene (target gene) area | regions.
43-2 shows the structure No. It is a figure which shows the base sequence of the plasmid which inserted DNA of the GFP gene in the 16 insertion gene (target gene) area | region (continuation of FIG. 43-1).
FIG. 44 is a diagram showing the intensity of GFP gene expression when a plasmid containing the SV40 promoter (construct No. 15) and the hTERT promoter (construct No. 16) is used.
FIG. 45 shows the nucleotide sequence of the human erythropoietin region in the plasmid.
FIG. It is a figure which shows the result at the time of expressing human erythropoietin using 14 plasmids.
FIG. 47A is a view showing a base sequence of a human IgG light chain region (FIG. 44A) in a plasmid.
FIG. 47B is a diagram showing a base sequence of a human IgG heavy chain region (FIG. 44B) in a plasmid.
FIG. It is a figure which shows the result at the time of expressing human IgG light chain (FIG. 48A) and human IgG heavy chain (FIG. 48B) using 14 plasmids.
FIG. FIG.
50 shows construct NO. It is a figure which shows the base sequence of the plasmid which inserted DNA of full length human REIC in the 17 insertion gene (target gene) area | region.
FIG. It is a figure which shows the result of having expressed full-length human REIC using 17 plasmids.
FIG. 52 is a diagram showing the sequence of the c-myc gene.
FIG. 53 shows construct no. It is a figure which shows the base sequence which BGH polyA and three enhancers which exist downstream of the expression gene of 14 expression plasmids connected.
FIG. 54 shows construct No. It is a figure which shows the result at the time of incorporating the base sequence which BGH polyA and three enhancers which exist downstream of the expression gene of 14 expression plasmids were integrated, and expressing a c-myc gene.
FIG. FIG.
FIG. It is a figure which shows the structure of 19. FIG.
FIG. FIG.
58 shows construct no. FIG.
59-1 shows the structure No. It is a figure which shows the base sequence of the plasmid which inserted DNA of the GFP gene in 21 insertion gene (target gene) area | regions.
59-2 shows the structure No. FIG. 59 is a diagram showing the base sequence of a plasmid in which GFP gene DNA is inserted into 21 inserted gene (target gene) regions (continuation of FIG. 59-1).
FIG. 60 shows the results when the target gene is inserted into a plasmid containing the hTERT promoter and expressed.
FIG. 61 is a diagram showing expression when a plurality of expression vectors incorporating different foreign genes are co-transfected.
FIG. 62 shows the production of human erythropoietin using the expression vector of the present invention.
FIG. 63 is a diagram showing the purity of human erythropoietin produced using the expression vector of the present invention.
FIG. 64 is a view showing the production amount of human erythropoietin using the expression vector of the present invention, FIG. 64A shows the production amount in 25 mL of culture supernatant, and FIG. 64B shows the equivalent production amount in 1 L of culture supernatant. Indicates.
FIG. 65 is a diagram showing production of human REIC protein using the expression vector of the present invention.
FIG. 66 is a diagram showing an ion exchange column chromatogram of human REIC protein produced using the expression vector of the present invention.
FIG. 67 is a diagram showing the production amount of human REIC protein (the production amount in 520 mL of culture supernatant and the equivalent production amount in 1 L of culture supernatant) using the expression vector of the present invention.

Hereinafter, the present invention will be described in detail.
In the present invention, the expression cassette for the protein to be expressed refers to a set of DNAs that enable the expression of the protein to be expressed.
The expression cassette includes a DNA construct containing a gene of a protein to be expressed (gene to be expressed) and a poly A addition sequence at least downstream of the first promoter, and further an enhancer downstream of the construct. Or it has the structure where the 2nd promoter is connected and contained. Any gene can be used for expression. In the expression cassette of the present invention, the site into which the gene to be expressed is inserted may exist as a multicloning site. In this case, the gene to be expressed may be inserted into the multicloning site (insertion site) using a sequence recognized by a restriction enzyme. The expression cassette of the present invention also includes an expression cassette that does not include the gene DNA itself to be expressed as described above and includes a portion into which the DNA is inserted as a multicloning site. A gene to be expressed may be called a target gene or target gene, and a protein may be called a target protein or target protein. From the viewpoint of constructing an expression cassette, these genes are also called insertion genes because they are inserted into the target gene region of the expression cassette. It may also be a foreign gene.
Further, the enhancer or the second promoter is present at the most downstream of the expression cassette of the present invention, and there is no other gene expression mechanism downstream thereof. That is, the expression cassette of the present invention has a structure in which at least a gene to be expressed is sandwiched between one first promoter and at least one enhancer, or between one first promoter and one second promoter. Have. Here, the other gene expression mechanism means a mechanism for expressing a gene other than the gene to be expressed, and a promoter or enhancer for expressing a gene other than the gene to be expressed. Etc. are included. In the expression cassette of the present invention, promoters may exist upstream and downstream of the gene to be expressed, but these two promoters are used for enhancing the expression efficiency of the gene to be expressed.
The expression cassette of the present invention is incorporated into an expression vector. The present invention also includes a vector comprising the expression cassette of the present invention. As described above, the enhancer or the second promoter is present in the most downstream of the expression cassette of the present invention, and there is no other gene expression mechanism downstream thereof. The vector containing the expression cassette of the present invention has no other gene expression mechanism downstream of the expression cassette.
In the present invention, the gene to be expressed includes a gene (DNA) encoding a foreign protein that has been artificially inserted, and includes genes that have different origins from host cells and genes that have the same origin. In this case, in the present invention, the foreign gene is also referred to as an inserted gene. The type of gene to be expressed is not limited. DNA encoding any protein for which a recombinant is to be produced, or DNA encoding a protein to be expressed in vivo for use in the treatment of a specific disease Can be used. Further, as therapeutic genes that can be used for the treatment of specific diseases, REIC / Dkk-3 gene (SEQ ID NO: 17 shows the nucleotide sequence), tumor suppressor genes such as p53 and Rb, interleukin 1 (IL-1), IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, IL-10, IL-11, IL-12, IL-13, IL- 14, IL-15, α-interferon, β-interferon, γ-interferon, angiostatin, thrombospondin, endostatin, METH-1, METH-2, GM-CSF, G-CSF, M-CSF, tumor necrosis Factors, hepatocyte growth factor, erythropoietin, thrombopoietin, insulin, growth hormone, antibody (IgG light chain or IgG heavy chain), protein G, protein A, etc. Proteins which can be used as medicaments, such as physiologically active substances, experiments in diagnostics and laboratories for use in the detection of such diseases include genes encoding proteins useful as a reagent for use in research or the like. The target protein to be expressed is preferably an extracellular secreted protein. Moreover, the expression of the gene inherent in the organism can be enhanced by artificially linking an enhancer or promoter downstream of the gene inherent in the organism. That is, the gene to be expressed in the present invention includes a gene originally possessed by an organism. Thus, the present invention also includes inserting an enhancer or promoter downstream of the gene inherent in the organism and controlling the expression of the gene. Moreover, the cell which inserted the enhancer or the promoter downstream of this gene of the cell containing the gene which an organism originally has is also included. Furthermore, examples of genes to be expressed include DNA encoding siRNA, shRNA, miRNA and the like having RNA interference action. When RNA having RNA interference action is used, expression of a specific gene can be suppressed by transcription-producing these RNAs using a transfer RNA promoter.
For example, among these genes, the REIC / Dkk-3 gene and the like can be used for tumor treatment, and not only the full-length gene but also a fragment thereof can be used. For example, REIC / Dkk-3 shown in SEQ ID NO: 18 An amino acid sequence starting with the first amino acid in the amino acid sequence of the protein and ending with any of the 39th amino acid to the 78th amino acid, or the amino acid sequence of the REIC / Dkk-3 protein shown in SEQ ID NO: 18; It comprises an amino acid sequence obtained by substituting, deleting, or adding one or several amino acids in the amino acid sequence starting with the first amino acid and ending with any of the 39th amino acid to the 78th amino acid, and has apoptotic activity DNA encoding a polypeptide having Among these DNAs, DNA encoding a peptide consisting of amino acids 1 to 78 of the amino acid sequence of the REIC / Dkk-3 protein shown in SEQ ID NO: 18 (N78-REIC DNA) is preferably used.
In addition, a reporter gene may be included for detection or diagnosis of a disease.
A promoter is a specific base sequence on DNA that initiates transcription using DNA as a template, and generally has a common sequence. For example, prokaryotes such as Escherichia coli usually have a TATAATG sequence at the −10 base pair site of the transcription initiation site and a TTGACA sequence at the −35 base pair site. In addition, eukaryotes usually have a TATA box at a -20 base pair site. The expression cassette of the present invention may necessarily have a first promoter upstream of the gene to be expressed, and may have a second promoter downstream of the gene to be expressed. The promoters used as the first promoter and the second promoter are not limited, and the first promoter and the second promoter may be the same or different. A non-specific promoter capable of promoting the expression of a foreign gene in any cell or tissue, and a specific or selective promoter such as a tissue or organ-specific promoter, a tumor-specific promoter, a developmental or differentiation-specific promoter, etc. can be used. For example, a specific promoter can be used as the first promoter, and a non-specific promoter can be used as the second promoter. As promoters used in the present invention, hTERT (human telomerase reverse transcriptase), PSA (prostate specific antigen), c-myc, GLUT promoter and the like are ES cell / cancer stem cell specific promoters. OCT3 / 4, NANOG promoter, etc., neural stem cell specific promoters such as Nestin promoter, cell stress sensing promoters such as HSP70, HSP90, p53 promoter, liver cell specific promoters such as albumin promoter, etc. Proliferative cell-specific promoters include TNF-alpha promoters as susceptibility promoters and SV40 promoters as promoters that increase the number of copies of infectious plasmids. Such as EF1-alpha promoter, and the like to. More specifically, for example, as the first promoter, CMV-i promoter (hCMV + intron promoter) (SEQ ID NO: 5), β-actin promoter, CAG promoter (SEQ ID NO: 12), CMV promoter and the like are used. A CMV promoter or the like is used as the promoter of the above. The animal species from which the β-actin promoter is derived is not limited, and a mammalian β-actin promoter such as a human β-actin promoter (SEQ ID NO: 8) or a chicken triactin promoter is used. Artificial hybrid promoters such as the above CMV-i promoter can also be used. The CMV-i promoter can be synthesized based on the description in US Pat. No. 5,168,062 and US Pat. No. 5,385,839. As the promoter, a core promoter portion consisting of a minimal sequence having promoter activity may be used. The core promoter refers to a promoter region having a function of inducing accurate transcription initiation, and may include a TATA box. Among the above promoters, cancer / tumor-specific promoters such as the hTERT promoter can be suitably used for gene therapy by gene expression and cancer diagnosis targeting cancer. 21 can be used for such applications.
The origin of the poly A addition sequence (polyadenylation sequence, polyA) is not limited, and is included in the growth hormone gene-derived poly A addition sequence, for example, the bovine growth hormone gene-derived poly A addition sequence (included in the base sequence shown in SEQ ID NO: 6). (Sequence after the 13th base)), poly A addition sequence derived from human growth hormone gene, poly A addition sequence derived from SV40 virus, poly A addition sequence derived from human or rabbit β-globin gene, and the like. Inclusion of a poly A addition sequence in an expression cassette increases transcription efficiency.
The enhancer is not limited as long as it enhances the amount of messenger RNA (mRNA) produced by transcription. An enhancer is a base sequence that has the effect of promoting the action of a promoter, and generally there are many that consist of around 100 bp. Enhancers can promote transcription regardless of sequence orientation. One type of enhancer may be used in the present invention, but a plurality of two or more identical enhancers may be used, or a plurality of different enhancers may be used in combination. Moreover, when using several different enhancer, the order is not limited. For example, a CMV enhancer (SEQ ID NO: 7), SV40 enhancer, hTERT (Telomerase Reverse transcriptase) enhancer, or the like can be used. As an example, a hTERT enhancer, an SV40 enhancer and a CMV enhancer connected in this order can be mentioned.
Furthermore, a plurality of enhancers, for example, 1 to 4 enhancers, may be linked upstream of the DNA construct containing the DNA encoding the protein to be expressed and the poly A addition sequence. The enhancer linked upstream is not limited, but a CMV enhancer is preferable. For example, 4 × CMV enhancer (SEQ ID NO: 11) in which four CMV enhancers are linked can be used.
When an enhancer is inserted immediately downstream of a DNA construct consisting of “promoter—gene to be expressed—poly A addition sequence”, protein expression of the gene to be expressed more strongly than conventional gene expression systems. Is possible.
In particular, the combination of the CMV i promoter and the CMV enhancer allows the strong expression of the gene to be expressed when any gene is inserted in almost all cells (host cells), regardless of the transfection reagent used. Protein expression is possible.
By inserting one or more CMV enhancers upstream of the promoter, in a specific cell (for example, HEK293 cell line or MCF7 cell line in the examples described later), a specific gene, for example, REIC / Dkk in the examples described later. Expression is further enhanced in the -3 gene and CD133 gene. Further, by inserting four CMV enhancers in front of the promoter, the expression is further enhanced depending on specific cells (for example, HepG2 cell line and HeLa cell line in Examples described later).
It should be noted that gene expression increases only slightly or changes only slightly by inserting a CMV enhancer upstream (FIGS. 1 and 2). In the expression cassette of the present invention, it is important that a CMV enhancer is inserted and linked immediately downstream of the poly A addition sequence.
Furthermore, RU5 ′ (SEQ ID NO: 9) may be linked immediately upstream of the DNA encoding the protein to be expressed. The term “immediately upstream” means that they are directly linked without intervening elements having other specific functions, but a short sequence may be included as a linker. RU5 ′ is an HTLV-derived LTR, and is an element that increases protein expression by insertion (Mol. Cell. Biol., Vol. 8 (1), p. 466-472, 1988). By inserting RU5 ′ in the reverse direction as reported, the effect of enhancing expression by inserting a promoter enhancer may be counteracted.
Furthermore, UAS may be linked immediately upstream of the enhancer and / or promoter. UAS is a binding region of the GAL4 gene, and protein expression is increased by inserting the GAL4 gene later.
Furthermore, SV40-ori may be connected to the uppermost stream of the expression cassette. SV40-ori is a binding region of the SV40 gene, and protein expression increases by inserting the SV40 gene later.
Each of the above elements needs to be functionally linked. Here, the term “functionally linked” means that each element is linked so as to enhance the expression of the gene to be expressed by exerting its function.
7 to 21, 36, 37, 49, 55 to 58 show the structures of various expression cassette constructs. In the present invention, the construct is also referred to as a plasmid backbone. As a construct that enhances the expression of a gene to be expressed according to the present invention, for example, construct No. 2 (FIG. 8), no. 4 (FIG. 10), no. 6 (FIG. 12), no. 8 (FIG. 14), no. 10 (FIG. 16), no. 12 (FIG. 18), no. 14 (FIG. 20), no. 15 (FIG. 36), no. 16 (FIG. 37), no. 17 (FIG. 49), no. 20 (FIG. 57) and no. 21 (FIG. 58). Further, the construct shown in FIG. 21 is also included.
Among these constructs, from the viewpoint of increasing gene expression, construct No. 3 in which three enhancers are linked downstream of the target gene. 14, construct no. 15 and construct no. Sixteen constructs are the best. For example, construct no. By using the REIC full-length gene as the target gene in 14, the protein expression level is comparable to that in the case of an adenovirus vector (encoding the full-length REIC / Dkk-3 gene) at 100 MOI. In addition, the construction No. The plasmid backbone of 14 shows an effect of increasing gene expression even in a gene fragment such as DNA encoding N78-REIC.
For example, construct no. By transfection of human prostate cancer cell PC3 with a preparation containing a DNA fragment encoding N78-REIC in 14 constructs, a remarkable cancer cell proliferation inhibitory effect and cancer cell death inducing effect are observed. Construct No. A cancer cell proliferation inhibitory effect is observed by transfecting human prostate cancer cell PC3 with a formulation encoding 14 full-length REIC genes in 14 constructs.
In addition, the construction No. A DNA encoding a protein such as human erythropoietin is inserted into 14 to prepare an expression vector, and the cell is transfected using the expression vector, whereby the protein can be produced in large quantities using the cell. .
In the present invention, the DNA represented by the nucleotide sequence of SEQ ID NO: has a mutation in the nucleotide sequence as long as it has the activity of each DNA or the activity of the protein or polypeptide encoded by each DNA. It may be. For example, DNA that hybridizes under stringent conditions with DNA having a base sequence complementary to the base sequence represented by each SEQ ID NO., The base sequence represented by each SEQ ID NO., And BLAST (Basic Local Alignment) At least 85% when calculated using Search Tool at the National Center for Biological Information (e.g., US National Biological Information Center Basic Local Alignment Search Tool)) (e.g., using default or default parameters) DNA having homology of preferably 90% or more, more preferably 95% or more, particularly preferably 97% or more, or a protein or a poly encoded by said DNA An amino acid sequence in which one, plural or several (1 to 10, preferably 1 to 5, more preferably 1 or 2) amino acids are substituted, deleted and / or added to the amino acid sequence of peptide. DNA encoding a protein or polypeptide consisting of can also be used for the construction of the DNA construct of the present invention. Here, “stringent conditions” are, for example, conditions of about “1XSSC, 0.1% SDS, 37 ° C.”, and more severe conditions are “0.5XSSC, 0.1% SDS, 42 ° C.” The condition is about “0.2XSSC, 0.1% SDS, 65 ° C.”. Thus, isolation of DNA having high homology with the probe sequence can be expected as the hybridization conditions become more severe. However, the combination of the above SSC, SDS, and temperature conditions is an example, and the necessary stringency can be realized by appropriately combining the DNA concentration, DNA length, hybridization reaction time, and the like. is there.
Examples of vectors for inserting the expression cassette of the present invention include plasmids, adenovirus vectors, adeno-associated virus vectors, lentivirus vectors, retrovirus vectors, herpes virus vectors, Sendai virus vectors, and other viral vectors and biodegradable polymers. Non-viral vectors can be mentioned. What is necessary is just to introduce | transduce the vector which introduce | transduced the said cassette for expression into a cell by well-known methods, such as infection and electroporation.
At this time, a known transfection reagent may be used.
By introducing a vector into which a cassette for expression of the present invention is inserted into a cell and transfecting the cell, a target gene can be expressed in the cell to produce a target protein. In order to introduce the expression cassette of the present invention and produce the target protein, a eukaryotic cell or a prokaryotic cell system can be used. Examples of eukaryotic cells include cells such as established mammalian cell lines, insect cell lines, filamentous fungal cells, and yeast cells. Examples of prokaryotic cells include E. coli, Bacillus subtilis, and Brevibacillus bacteria. Bacterial cells are mentioned. Preferably, mammalian cells such as Hela cells, HEK193 cells, CHO cells such as CHO, COS cells, BHK cells, Vero cells are used. The transformed host cell can be cultured in vitro or in vivo to produce the target protein. Host cells are cultured according to a known method. For example, a known culture medium such as DMEM, MEM, RPMI 1640, and IMDM can be used as the culture solution. The expressed protein can be purified by a known method from a culture solution in the case of a secreted protein or from a cell extract in the case of a non-secreted protein. When expressing and producing a target protein, a cell may be produced by simultaneously transfecting a plurality of vectors containing different target genes. By doing so, a plurality of proteins can be produced at one time.
Furthermore, a commercially available vector may be modified to include the expression cassette of the present invention. For example, an enhancer can be incorporated into the downstream region of the expression gene cassette of a commercially available vector such as a pShuttle vector. The vectors of the present invention include those obtained by modifying commercially available cassettes.
The present invention further includes an adenovirus (Ad) vector and an adeno-associated virus (AAV) vector containing the above-described cassette for gene expression to be expressed. The vector enables specific diagnosis or treatment of diseases such as cancer. The vector can be prepared by inserting the above-described gene expression cassette into adenovirus or adeno-associated virus.
The characteristics of adenovirus vectors are (1) gene transfer into many types of cells, (2) gene transfer into cells in growth arrested phase efficiently, and (3) concentration by centrifugation. High titer (10 to 11 PFU / ml or more) virus can be obtained, and (4) suitable for direct gene transfer into tissue cells in vivo.
As an adenovirus for gene therapy, a first generation adenovirus vector lacking the E1 / E3 region (Miyake, S., et.
al. , Proc. Natl. Acad. Sci. USA. , 93, 1320, 1996), a second generation adenoviral vector (Lieber, A., et. Al.) Lacking the E2 or E4 region in addition to the E1 / E3 region.
al. , J .; Virol. , 70, 8944, 1996; Mizuguchi, H .; & Kay, M .; A. , Hum. Gene Ther. , 10, 2013, 1999), the adenoviral genome almost completely deleted (GUTLESS), a third generation adenoviral vector (Steinwaerder, DS, et al., J. Virol., 73, 9303, 1999) has been developed, but the gene according to the present invention is not particularly limited, and any adenoviral vector can be used.
Adeno-associated virus is a parvovirus genus single-stranded DNA virus, and has the characteristics of (1) gene long-term expression, (2) low toxicity, and (3) gene transfer into dividing and non-dividing cells. The formation of concatamers (complexes in which single-stranded DNAs are linked) is the cause of long-term gene expression.
The adenovirus (Ad) vector and the adeno-associated virus (AAV) vector that contain the cassette for expression of the gene to be expressed of the present invention and can express the target gene to be expressed are used for disease detection or treatment. Can be used. Diseases include cancer and the like, and the cells are directed by a peptide such as RGD that selectively binds to a protein expressed in a specific cell inserted into the outer shell of an adenovirus vector or an adeno-associated virus vector. , A gene that infects and expresses the cells is expressed. When the gene to be expressed is a reporter gene such as a luciferase gene, specific cells can be detected by luminescence or the like. When a specific cell is a cancer cell, by administering to a subject, the cancer cell in a subject can be detected and it can be diagnosed that the subject is suffering from cancer. Since the adenovirus vector and adeno-associated virus vector of the present invention can detect one cell, they can be used, for example, for detection of microcancer.
In addition, when the gene to be expressed is a therapeutic gene, the target gene to be expressed in a specific cell is expressed, and a therapeutic effect can be exhibited. For example, when a specific cell is a cancer cell and a cancer suppressor gene such as REIC / Dkk-3 gene is used, the gene for cancer treatment is delivered to the cancer cell of the subject by administration to the subject, and the cancer Genes are expressed in cells and exert therapeutic effects. The present invention includes a diagnostic or therapeutic viral preparation comprising such an adenoviral vector or an adeno-associated viral vector. As a cancer to be treated when a tumor suppressor gene such as a human REIC / Dkk-3 gene is used as a therapeutic gene, examples of the cancer to be treated according to the present invention include brain / neural tumors, skin cancers, and the like. , Stomach cancer, lung cancer, liver cancer, lymphoma / leukemia, colon cancer, pancreatic cancer, anal / rectal cancer, esophageal cancer, uterine cancer, breast cancer, adrenal cancer, renal cancer, renal pelvic and ureteral cancer, bladder cancer, prostate cancer, urethral cancer, penis Examples include cancer, testicular cancer, bone / osteosarcoma, leiomyoma, rhabdomyosarcoma, and mesothelioma. The adenovirus vector and adeno-associated virus vector of the present invention can be used for the treatment of primary cancer and metastatic cancer.
The adenovirus vector and adeno-associated virus vector of the present invention can be used in the gene therapy field, for example, intravascular administration such as intravenous administration and intraarterial administration, oral administration, intraperitoneal administration, intratracheal administration, bronchial administration, and the like. It can be administered by internal administration, subcutaneous administration, transdermal administration, or the like. In particular, the adenovirus vector and adeno-associated virus vector of the present invention are highly directed to specific tissues and cells, and can efficiently deliver target genes to specific tissues and cells. Efficient diagnosis and treatment.
The adenovirus vector and adeno-associated virus vector may be administered in a therapeutically effective amount. A therapeutically effective amount can be readily determined by one skilled in the art of gene therapy. Furthermore, the dose can be appropriately changed depending on the severity of the disease state, sex, age, weight, habits, etc. of the subject. For example, an adenovirus vector and an adeno-associated virus vector may be 0.5 × 10 ^{11 to} 2.0 × 10 ¹² viral genome / kg body weight, preferably 1.0 × 10 ^{11 to} 1.0 × 10 ¹² viral genome / It may be administered in an amount of kg body weight, more preferably 1.0 × 10 ^{11 to} 5.0 × 10 ¹¹ viral genome / kg body weight. The virtual genome indicates the number of molecules (number of virus particles) of the genome of adenovirus or adeno-associated virus, and is sometimes referred to as particle. Contains carriers, diluents and excipients commonly used in the pharmaceutical field. For example, lactose and magnesium stearate are used as carriers and excipients for tablets. As an aqueous solution for injection, isotonic solutions containing physiological saline, glucose and other adjuvants are used, and suitable solubilizers such as polyalcohols such as alcohol and propylene glycol, nonionic surfactants, etc. You may use together. As the oily liquid, sesame oil, soybean oil and the like are used, and as a solubilizing agent, benzyl benzoate, benzyl alcohol and the like may be used in combination.
Furthermore, an expression vector containing the expression cassette of the present invention containing the gene of interest can also be used as a vaccine or DNA vaccine for cancer or the like (Kaufman, HL et al., J. Clin. Oncol. 22, 2122-2132). (2004); McNeel, DG et al., J. Clin. Oncol. 27, 425-430 (2009)). For example, a cancer-specific antigen is used as a target protein, and an expression vector containing the expression cassette of the present invention incorporating a gene encoding the protein is administered into a living body by subcutaneous injection or the like, and the antigen is expressed in the living body. And activation of cellular immunity and antibody immunity of the host against the antigen can be induced. Thus, by using it as a vaccine, the expression cassette of the present invention can be used for prevention and treatment of diseases such as cancer.
The present invention will be specifically described by the following examples, but the present invention is not limited to these examples.

Expression Cassette Containing CMV Promoter The expression cassette of the present invention was prepared and transfected, and the expressed protein was analyzed by Western blot.
(1) Construct No. of the expression cassette used 1 (Fig. 7)
It is a gene expression plasmid carrying a CMV i promoter upstream of a gene to be expressed. Further, BGH polyA (bovine growth hormone polyA additional sequence) is linked downstream of the gene. That is, it is considered that the protein expression ability is equivalent to that of an expression plasmid using a CMV i promoter that is generally used.
Construct No. 2 (Fig. 8)
Construct No. CMV enhancer is inserted immediately downstream of 1 BGH poly A.
Construct No. 3 (Fig. 9)
Construct No. One CMV i promoter is replaced with the human β-actin promoter.
Construct No. 4 (Fig. 10)
Construct No. The CMV enhancer was inserted immediately downstream of the 3 BGH poly A.
Construct No. 5 (Fig. 11)
Construct No. The RU5 ′ region is inserted immediately downstream of the 3 human β-actin promoter.
Construct No. 6 (Fig. 12)
Construct No. A CMV enhancer was inserted immediately downstream of 5 BGH poly A.
Construct No. 7 (Fig. 13)
Construct No. A CMV enhancer is inserted immediately upstream of the human β-actin promoter.
Construct No. 8 (Fig. 14)
Construct No. A CMV enhancer was inserted immediately downstream of 7 BGH poly A.
Construct No. 9 (Fig. 15)
Construct No. 7 in which the RU5 ′ region has a reverse base sequence.
Construct No. 10 (FIG. 16)
Construct No. A CMV enhancer is inserted immediately downstream of 9 BGH poly A.
Construct No. 11 (Fig. 17)
Construct No. A 4 × CMV enhancer (4 CMV enhancers) is inserted immediately upstream of the 5 human β-actin promoter.
Construct No. 12 (Fig. 18)
Construct No. CMV enhancer is inserted immediately downstream of 11 BGH poly A.
Construct No. 13 (FIG. 19)
It is a gene expression plasmid carrying a CAG promoter. That is, it is considered that the protein expression ability is equivalent to that of an expression plasmid using a commonly used CAG promoter.
Construct No. 14 (FIG. 20)
As a result of examining the above various constructs so far, it was found that gene expression was significantly enhanced by inserting a CMV enhancer immediately downstream of BGH poly A. In 14, the other enhancer, hTERT enhancer and SV40 enhancer were linked. As a result, construct no. It is thought that it became a construct superior to 2.
Adenovirus construct encoding the full-length REIC / Dkk-3 gene (FIG. 21)
REIC / Dkk-3 (Ad-REIC) full-length cDNA was incorporated into the cosmid vector pAxCAwt, and then transferred to an adenovirus vector by COS-TPC method (TAKARA Bio). At this time, an adenovirus vector (Ad-LacZ) carrying the LacZ gene was used as a control. The adenovirus vector used is the same as that described in Japanese Patent No. 3813872.
22 to 35 show the base sequences of the following elements or constructs.
FIG. 22-1 and FIG. 22-2 (continuation of FIG. 22-1) show the entire base sequence of pDNR-1r Donor vector (a plasmid vector for cloning without promoter (Clontech, product number PT3616-5)).
FIG. 23 shows the entire base sequence of pIDT-SMART vector (plasma vector for cloning without promoter (IDT)).
FIG. 24 shows the nucleotide sequence of the CMV i promoter (hCMV + intron promoter) region. The region was created by artificial synthesis based on the known information of the base sequence of the CMV i promoter region.
FIG. 25 shows the base sequence of the BGH polyA (3 × stop + BGH polyA) region.
The part of “TAATAAA” in the base sequence is a more important sequence in the BGH polyA sequence. The sequence was prepared by artificial synthesis based on the known information of the base sequence of the BGH polyA region.
FIG. 26 shows the base sequence of the CMV enhancer region. The sequence was prepared by artificial synthesis based on the known information of the base sequence of the CMV enhancer region.
FIG. 27 shows the base sequence of the human β-actin promoter region. The sequence was prepared by obtaining a plasmid for pDRIVE-hβActin-RU5 ′ from InvivoGen, and PCR amplifying the nucleotide sequence of that portion.
FIG. 28 shows the base sequence of RU5 ′ forward direction {HTLV Type 1 long terminal repeat R segment and part of U5 sequence (R-U5 ′)} region. The sequence was prepared by artificial synthesis based on the known information of the base sequence of the R segment of {HTLV Type 1 long terminal repeat and part of U5 sequence (R-U5 ′)} region.
FIG. 29 shows the base sequence of the RU5 ′ reverse direction {HTLV Type 1 long terminal repeat R segment and part of the U5 sequence (R-U5 ′)} region. The sequence was prepared by artificial synthesis based on the known information of the base sequence of the R segment of {HTLV Type 1 long terminal repeat and part of U5 sequence (R-U5 ′)} region.
FIG. 30 shows the base sequence of the 4 × CMV enhancer region. The underlined portion of the base sequence in FIG. 30 is called a so-called “short CMV enhancer”, and since there are four, it becomes a 4 × CMV enhancer. The above-mentioned CMV enhancer includes a “short CMV enhancer”, and generally speaking, the CMV enhancer indicates the longer one. The sequence was prepared by artificial synthesis based on the known information of the base sequence of the CMV enhancer region.
FIG. 31 shows the base sequence of the CAG promoter region. This is the base sequence of a known CAG promoter region. Based on the pCAGGS plasmid, which is a gene expression vector loaded with the CAG promoter, provided by Oriental Yeast Co., Ltd., it was prepared by PCR amplification of the nucleotide sequence of that portion.
FIG. 32 shows the base sequence of the 2IRES insert region. It is a base sequence of the IRES control gene of FIG.5 and FIG.6 of postscript. BiP-IRES region (lowercase part enclosed in frame (1) in base sequence of FIG. 32) and Myc-IRES region (lowercase part enclosed in frame (2) in base sequence of FIG. 32) The base sequence of two normal human DNAs is connected in this order, and is a gene used as a control gene for inserted genes. The sequence was prepared by artificial synthesis based on the known information of the base sequences of the BiP-IRES region and Myc-IRES region.
FIG. 33 shows the nucleotide sequence of the SV40ori-UAS-CMVi-RU 5 ′ region. Construct No. It is the base sequence of the insertion part on the left side of the insertion gene (foreign gene) of 14 (best construct). The sequence was prepared by artificial synthesis based on the known information of the base sequence of each region included in the part. In the base sequence of FIG. 33, the part surrounded by the frame (1) shows the SV40 ori region, the part enclosed by the frame (2) shows the CMV i promoter region, and the part enclosed by the frame (3) shows , RU5 ′ region.
FIG. 34 shows the base sequence of the 3 × stop-BGH-polyA-UAS-hTERT enhancer + SV40 enhancer + CMV enhancer region. Construct No. 14 is the base sequence of the insertion part on the right side (downstream side) of the insertion gene (foreign gene) of 14 (best construct). The sequence was prepared by artificial synthesis based on the known information of the base sequence of each region included in the part. In the base sequence in FIG. 34, the uppercase part surrounded by the frame (1) encloses the BGH polyA region, and the lowercase part enclosed by the frame (2) encloses the hTERT enhancer region by the frame (3). The uppercase part indicates the SV40 enhancer region, and the lowercase part surrounded by the frame (4) indicates the CMV enhancer region.
35-1 and 35-2 show the structure No. The full base sequence of 14 vectors is shown. The construct No. shown in FIG. 14 (best construct) base sequence, pIDT-SMART vector part (the region up to the bold part of the 10th line of the base sequence in FIG. 35-1 and 24 lines from the bottom of the base sequence in FIG. 35-2) All base sequences including the region behind GGCGCC surrounded by a frame). The sequence was prepared by incorporating the inserted portions (foreign gene) on the left and right shown in the previous two (construct No. 14) into the pIDT-SMART vector described above. (1) is SV-40 ori region, (2) is CMV i promoter region, (3) is RU5 ′ region, (4) is BiP IRES region, (5) is Myc IRES region, (6) Indicates the hTERT enhancer region, and (7) indicates the SV40 enhancer region.
(2) Foreign gene used (inserted gene)
6His-S100A11-HA
Using the cDNA of human normal fibroblasts as a template, PCR was prepared using a primer with a 6His linker on the 5 'side and a primer with an HA linker on the 3' side.
GFP (Green Fluorescent Protein)
Primers were set using pEGFP-N2, a GFP expression vector of Clontech, as a template, and PCR was performed.
REIC / Dkk-3 (full length)
Primers were set using the cDNA of human normal fibroblasts as a template, and PCR was performed.
N78-REIC-6His
Primers were set so that 6His was attached to the 3 ′ side of the full-length REIC / Dkk-3 gene obtained above, and PCR was performed.
Control gene (IRES)
This IRES control gene referred to here is obtained by linking known base sequences of two normal human DNAs of BiP-IRES gene and Myc-IRES gene in this order, and was prepared by artificial synthesis. This gene was designated as construct no. By inserting it into the 14 inserted genes (foreign genes), it was used as a control gene for DNA encoding REIC / Dkk-3 (full length) gene and N78-REIC-6His in FIGS.
CD133-6His
Primers were set using the cDNA of human normal fibroblasts as a template, and PCR was performed.
LGR5-HA
Primers were set using the cDNA of human normal fibroblasts as a template, and PCR was performed.
Telomerase-6His
Primers were set using the cDNA of human normal fibroblasts as a template, and PCR was performed.
KLF16
Primers were set using the cDNA of human normal fibroblasts as a template, and PCR was performed.
(3) Transfection method and Western blot analysis (WB method)
Introduction of various genes into various cells (cultured 70 to 80% confluent in 6-well plates) was carried out using transfection reagents from each company: FuGENE (trademark) -HD (Roche), Lipofectamine (registered trademark) 2000 ( Invitrogen) and Trans-IT-Keratinocyte (TAKARA Bio). The procedure was performed as described in the manual for each product.
Western blot analysis of the expressed foreign gene (inserted gene) was performed by the following method.
The cells were washed twice using PBS (phosphate buffered saline), and lysis buffer (50 mM HEPES, pH 7.4, 250 mM NaCl, 1 mM EDTA, 1% NP-40, 1 mM DTT, 1 mM PMSF, 5 μg / ml leupeptin, 5 μg) / Ml aprotinin, 2 mM Na ₃ VO ₄ , 1 mM NaF, 10 mM β-GP), and the protein was extracted. After centrifugation, the amount of protein in each supernatant used in each experiment was adjusted to the same concentration and diluted with the same amount of 2 × SDS sample buffer. Subsequently, it heat-processed for 5 minutes at 95 degreeC. Samples (10 μg protein) were separated by 7.5% or gradient SDS-PAGE gel (Bio Rad) and transferred to a poly (vinylidene fluoride) (PVDF) membrane. The blot was blocked with TBS (Tris buffered saline) containing 10% fat-free milk powder, 6% glycine and 0.1% Tween-20 for 1 hour at room temperature. The protein was then identified using the following primary antibody (1: 1000 dilution).
Anti-HA antibody (Cell Signaling Technology)
Anti-GFP antibody (Clontech)
Anti-REIC antibody (rabbit anti-human REIC / Dkk-3 polyclonal antibody)
Anti-6His antibody (MBL)
Anti-KLF16 antibody (Abcam)
Wash well with TBS containing 0.1% Tween-20 (T-TBS) and react the blot with horseradish peroxidase conjugated secondary antibody. After thorough washing with T-TBS, detection was performed by an enhanced chemiluminescence detection method (ECL kit, Amersham Pharmacia Biotech).
Cell culture was performed by the following method.
Each cell line of HEK293 (derived from human normal kidney), MCF7 (derived from human breast cancer), PC3 (derived from human prostate cancer), HeLa (derived from human uterine cancer), HepG2 (derived from human liver cancer) is ATCC (the American Type Culture Collection). (Rockville, MD). The medium used was as follows.
HEK293: DMEM high glucose medium (Invitrogen)
MCF7: DMEM high glucose medium (Invitrogen)
PC3: F12 medium (Invitrogen)
HeLa: DMEM high glucose medium (Invitrogen)
HepG2: DMEM high glucose medium (Invitrogen)
The cell line was grown in the above medium supplemented with 10% (v / v) fetal bovine serum, penicillin (100 IU / ml) and streptomycin (100 μg / ml) and incubated under 5% CO 2 conditions.
The results are shown in FIGS.
FIG. 1 shows the expression of various foreign genes transfected into HEK293 cell line using FuGENE ™ -HD for 36 hours. Construct No. The protein expression ability of 1 was equivalent to that of an expression plasmid using a CMV i promoter that is generally used (sold). That is, compared with the protein expression ability of these expression plasmids, the construct No. It can be said that the protein expression power of 2 is remarkably strong. In addition, similar results were obtained for the following various genes. 2 can be said to surpass the currently widely used gene expression system in the expression of all kinds of genes.
S100A11: considered to be involved in cancer growth; intracytoplasmic-nuclear translocation protein GFP: fluorescent protein; cytoplasmic protein REIC / Dkk-3 (full length): tumor suppressor protein; secretory protein N78-REIC: Originally produced fragment protein (fragment peptide consisting of amino acids 1 to 78 of the amino acid sequence of REIC / Dkk-3 protein shown in SEQ ID NO: 2)
CD133: Marker of cancer stem cells; also expressed on the cell surface LGR5: Marker of stem cells of normal cells and cancer cells; Transmembrane protein Telomerase: Involved in cell senescence and immortalization; Intracytoplasmic protein KLF16: Involved in protein transcription; Nucleus Inner protein FIG. 2 shows the expression of the KLF gene transfected into various cell lines with FuGENE ™ -HD for 36 hours. In all the cells shown in the figure (HEK293 cells, MCF7 cells, PC3 cells, HeLa cells, HepG2 cells), the construct No. 2 protein expression (KLF16 gene expression) It can be said that it is significantly stronger than 1. That is, the construct No. 2 can be said to surpass the currently widely used gene expression system in gene expression in all types of cells.
FIG. 3 shows the expression of the KLF gene transfected into the HEK293 cell line for 36 hours using various transfection reagents. In any transfection reagent, no. In the case of 2, the most KLF16 protein is expressed by the WB method. Construct No. 1 is a construct containing a CMV i promoter that is generally available and commonly used. 13 is a construct containing a CAG promoter which is also commonly used. That is, protein expression in an amount that significantly surpasses constructs that are currently widely used and used as plasmid constructs for gene expression all over the world (improvement of the efficiency of the entire gene expression process). Made possible by using 2.
FIG. 4 shows the expression when the HEK293 cell line was transfected for 36 hours using the full-length REIC gene and the gene FuGENE ™ -HD encoding N78-REIC. The left panel shows the structure No. by WB method. In construct No. 14, construct no. It shows that REIC / Dkk-3 protein (full length) is expressed more than in the case of 2. That is, the results of the WB method in Fig. 1 (No. 2 expresses the most protein among the constructs No. 1 to No. 12) and the results of the WB method in Fig. 3 (construct No. 1, No. 2, No. 2). .11, No. 12, No. 13, No. 2 expresses the most protein) Among the plasmid constructs examined, the construct that can express the most protein (useful) is the construct No. . 14. This construct No. The protein expression ability by 14 was as strong as that of Ad-REIC (adenovirus encoding full-length REIC / Dkk-3 gene) at 100 MOI. The right panel shows N78-REIC-6His which is a fragment gene. 14 shows that the same can be said for the left panel. That is, the most useful protein expression among the displayed plasmid constructs (useful) is the construct No. 14.
FIG. 5 shows construct No. in which DNA encoding N78-REIC was inserted. 14 shows growth suppression and cell death induction of human prostate cancer cell PC3 cell line by No. 14.
Cell viability assay PC3 cell lines were seeded in complete media at a density of 50,000 cells per well in 6-well plates. After 24 hours of incubation, the cells were transfected into a given plasmid using FuGENE ™ -HD reagent in complete medium and incubated for a given number of days. After the incubation, cell viability was measured using CellTiter 96 (registered trademark) Aquaone One Solution Cell Proliferation Assay (Promega).
Statistical analysis Mann-Whitney U test was performed between the two groups, and it was determined that there was a significant difference when p <0.05.
As shown in the figure, the construct No. in which DNA encoding N78-REIC was inserted was used. On the 2nd and 5th day after the administration of No. 14, the construct No. with the control gene (IRES) inserted therein was inserted. The proliferation of the PC3 cell line was significantly suppressed as compared with the administration group of 14 (the number of PC3 cells was significantly increased because the number of PC3 cells was reduced by the administration of DNA-construct No. 14 encoding N78-REIC. Can be said to have been induced).
FIG. 6 shows construct No. in which full-length REIC gene was inserted. 14 shows growth inhibition of human prostate cancer cell PC3 cell line by 14;
Cell viability assay PC3 cell lines were seeded in complete media at a density of 50,000 cells per well in 6-well plates. After 24 hours of incubation, cells were transfected into a given plasmid using FuGENE ™ -HD reagent in Hank's Balanced Salt Solutions and incubated for a given number of days. After the incubation, cell viability was measured using CellTiter 96 (registered trademark) Aquaone One Solution Cell Proliferation Assay (Promega).
Statistical analysis Mann-Whitney U test was performed between the two groups, and it was determined that there was a significant difference when p <0.05.
As shown in FIG. On the second day after administration of No. 14, the construct No. into which the control gene (IRES) was inserted was inserted. Compared with the 14 administration group, the proliferation of PC3 cells was significantly suppressed.

Expression cassette containing SV40 promoter or hTERT promoter An expression cassette according to the present invention containing GFP (Green fluorescein protein) as a target gene (inserted gene) is prepared, expressed by transfecting Hela cells and observing GFP expression Was analyzed for strength. Transfections were performed using Lipofectamine 2000, and GFP expression was observed under a fluorescence microscope 48 hours later.
The construct of the expression cassette used was the construct No. used in Example 1. 14 (FIG. 20) and construct no. Construct No. 14 in which CMV i promoter of 14 was replaced with SV40 promoter. 15 (FIG. 36) and construct no. Construct No. 14 in which the CMVi promoter of 14 was replaced with the hTERT promoter. 16 (FIG. 37). The GFP gene was prepared by setting a primer using pEGFP-N2, which is a GFP expression vector manufactured by Clontech, as a template, and inserting it into the target gene insertion part of each construct for use. As a control, a commercially available GFP expression plasmid pEGFP-N1 (Clontech) was used.
Construct No. The base structure of a partial fragment consisting of the 15 expression vector SV40 ori + UAS + SV40 enh + intron A + RU5 ′ regions is shown in FIG. 38, and its base sequence is shown in SEQ ID NO: 19. In addition, the construction No. The structure of a partial fragment consisting of 16 expression vectors SV40 ori + UAS + hTERT enh + intron A + RU5 ′ is shown in FIG. 39, and the nucleotide sequence is shown in SEQ ID NO: 20. Furthermore, FIG. 40 shows the base sequence of DNA encoding GFP linked with a restriction enzyme site (SEQ ID NO: 21). The portions surrounded by the frames (1), (2), (3) and (4) in the base sequence of FIG. 38 indicate SV40 ori, SV40 promoter, intron A and RU5 ′, respectively, and the base sequence of FIG. The part enclosed by the frame of (1), (2), (3) and (4) in the inside shows SV40 ori, hTERT promoter, intron A and RU5 ′, respectively. Construct No. The full-length base sequence of the vector in which the GFP gene is inserted into 14 expression vectors is shown in FIGS. 41-1 and 41-2 (continuation of FIG. 41-1) (SEQ ID NO: 22). In addition, the construction No. The full-length base sequences of vectors obtained by inserting the GFP gene into 15 expression vectors are shown in FIGS. 42-1 and 42-2 (continuation of FIG. 41-1) (SEQ ID NO: 23). Furthermore, construct no. The full-length base sequence of the vector in which the GFP gene is inserted into 16 expression vectors is shown in FIGS. 43-1 and 43-2 (continuation of FIG. 43-1) (SEQ ID NO: 24). In the base sequences of FIGS. 41-1 and 41-2, the parts surrounded by the frames (1), (2), (3) and (4) are the CMVi promoter (P-CMViRU), GFP gene, Myc, respectively. IRES, 3 enhancers (pA-3enh) are shown, and the portions surrounded by the frames (1), (2), (3) and (4) in the base sequence of FIG. 42 are SV40 promoter (P-SViRU). ), GFP gene, Myc IRES, 3 enhancers (pA-3enh), and the portions surrounded by the frames (1), (2), (3) and (4) in the base sequence of FIG. The hTERT promoter (P-TiRU), GFP gene, Myc IRES, and 3 enhancers (pA-3enh) are shown.
Construct No. 15 is a plasmid vector advantageous for strong gene expression in an environment where SV40 protein is highly expressed. 16 is a plasmid vector that is advantageous for strong gene expression in an environment where hTERT protein is highly expressed in cancer cells and the like.
The results are shown in FIG. 44A, B, C and D respectively show a commercially available GFP expression plasmid (pEGFP-N1), construct No. 14 GFP expression plasmid, construct no. 15 GFP expression plasmids, and construct no. The results of 16 GFP expression plasmids are shown. The upper panel in the figure shows a bright field. As shown in the figure, strong GFP gene expression was observed in all of the CMV promoter, SV40 promoter and hTERT promoter as compared with the commercially available plasmid. This example shows that the present system (construct skeleton of construct No. 14) can be used for gene enhancement even if the promoter is changed in this way.

Expression of human erythropoietin An expression cassette of the present invention containing human erythropoietin as a foreign gene (inserted gene) was prepared, HEK293 cells were transfected, and the expressed protein was analyzed by Western blot. The transfection was performed using FuGENE ™ -HD, and human erythropoietin in the cell culture medium was detected by Western blotting after 24 hours.
The construct of the expression cassette used was the construct No. used in Example 1. 14 (FIG. 20), and DNA encoding human erythropoietin was inserted as a target gene (inserted gene). FIG. 45 shows the base sequence of DNA encoding human erythropoietin linked with a restriction enzyme site (SEQ ID NO: 25). As a control, commercially available expression plasmids pTracer (registered trademark) -EF / V5-His-A (Invitrogen) and pEF6 / Myc-His-A (Invitrogen) were used, and the restriction enzyme sites EcoR1- of each plasmid were used. DNA encoding human erythropoietin was inserted into the site of Xba1.
Western blotting was performed using an anti-6His antibody (MBL), and 1 mL of the culture solution 24 hours after transfection was trapped and recovered with 6His amino acid, and the total amount of the recovered protein was used for Western blotting.
The results are shown in FIG. Lane 1 is expressed using pTracer (registered trademark) -EF / V5-His-A, Lane 2 is expressed using pEF6 / Myc-His-A, and Lane 3 is a construct No. Those expressed using 14 expression plasmids are shown. As shown in FIG. The strongest expression was observed when 14 expression plasmids were used. This result shows that this system (construct skeleton of construct No. 14) is useful from the viewpoint of quantitative production based on gene enhancement for the production of pharmaceuticals such as erythropoietin, proteins used as diagnostics, or reagents. Show.

Expression of human IgG An expression cassette of the present invention containing human IgG light chain and human IgG heavy chain as a target gene (inserted gene) was prepared, HEK293 cells were transfected, and the expressed protein was analyzed by Western blot. The transfection was performed using FuGENE ™ -HD, and human IgG light chain and human IgG heavy chain in the cell extract and cell culture medium were detected by Western blotting after 24 hours.
The construct of the expression cassette used was the construct No. used in Example 1. 14 (FIG. 20), and a DNA encoding human IgG light chain or human IgG heavy chain was inserted as a target gene (inserted gene). FIG. 47 shows the base sequences of DNAs encoding human IgG light chain (FIG. 47A) and human IgG heavy chain (FIG. 47B) linked with restriction enzyme sites (SEQ ID NO: 26 and SEQ ID NO: 27, respectively). As a control, commercially available expression plasmids pTracer (registered trademark) -EF / V5-His-A (Invitrogen) and pEF6 / Myc-His-A (Invitrogen) were used, and the restriction enzyme sites EcoR1- of each plasmid were used. DNA encoding human IgG light chain or human IgG heavy chain was inserted into the Xba1 site.
Western blotting was performed using an anti-6His antibody (MBL), and the cell extract 24 hours after transfection (total protein amount was 10 μg) and 1 mL of the culture solution were trapped with 6His amino acid and recovered. The total amount of protein was used.
The results are shown in FIG. FIG. 48A shows the result of human IgG light chain, and FIG. 48B shows the result of human IgG heavy chain. 48A and 48B, both lane 1 was expressed using pTracer (registered trademark) -EF / V5-His-A, lane 2 was expressed using pEF6 / Myc-His-A, and lane 3 was Construct No. What was expressed using 14 is shown. Moreover, the result of intracellular expression using a cell extract and the result using a culture solution are shown. As shown in FIG. The strongest expression was observed when 14 was used. This result shows that this system (construct skeleton of construct No. 14) is useful from the viewpoint of quantitative production based on gene enhancement for the production of proteins used as pharmaceuticals such as antibodies, diagnostic agents or reagents. .

Expression of REIC protein using an expression vector obtained by modifying a commercially available plasmid vector An expression cassette of the present invention containing the human REIC gene as a foreign gene (inserted gene) is prepared, and HEK293 cells are transfected, and the expressed protein is westernized. Analyzed by blot. The transfection was performed using FuGENE ™ HD, and after 24 hours, the REIC protein in the cell extract was detected by Western blotting.
The construct of the expression cassette used was the insertion site of Kpn1-EcoR1 downstream of the DNA encoding REIC by inserting the DNA encoding REIC into the Xba1-Kpn1 insert of a commercially available pShuttle plasmid vector (Clontech). The construct No. used in Example 1 Construct No. 14 (FIG. 20) was constructed by inserting three enhancers (hTERT enhancer, SV40 enhancer and CMV enhancer) downstream of the expression gene of the expression plasmid in the form of BGH poly A + 3 enhancers. 17 (FIG. 49). As a control, a vector constructed by inserting a DNA encoding REIC into the insertion part of Xba1-Kpn1 of a commercially available pShuttle plasmid vector (Clontech) was used. FIG. 50 shows a construct No. in which DNA encoding REIC is inserted. The entire base sequence of 17 expression vectors is shown (SEQ ID NO: 28). In the base sequence of FIG. 50, the portions surrounded by the frames (1) and (2) indicate DNA encoding REIC and three enhancers (3xenh), respectively.
Western blotting was performed using an anti-REIC antibody, and a cell extract 24 hours after transfection (total protein amount was 10 μg) was used.
The results are shown in FIG. Lane 1 is a result of cell extract of cells not expressing a foreign protein, Lane 2 is a result of cell extract of cells transfected with a vector encoding REIC into a commercially available pShuttle vector, Lane 3 is a commercially available pShuttle vector The results of cell extracts of cells transfected with an expression vector in which DNA encoding REIC is inserted and further 3 enhancers are inserted downstream of the DNA encoding REIC (downstream of BGH poly A) are shown. As shown in FIG. The strongest expression was observed when 17 was used. This result shows that the expression of the gene can be enhanced by incorporating the three enhancer parts of this system (construct backbone of construct No. 14) downstream of the expression gene cassette of a commercially available plasmid such as pShuttle vector. Indicates. That is, it is shown that it is possible to enhance the expression of the target gene by inserting three enhancer regions into various gene constructs.

Expression of c-myc gene using expression vector obtained by modifying commercially available plasmid vector An expression cassette of the present invention containing human c-mycC gene as a target gene (inserted gene) is prepared, and HEK293 cells are transfected, The expressed protein was analyzed by Western blot. Transfections were performed using FuGENE ™ -HD, and after 24 hours, the REIC protein in the cell extract was detected by Western blotting.
The construct of the expression cassette used was the insertion site of Kpn1-EcoR1 downstream of the DNA encoding REIC by inserting the DNA encoding REIC into the Xba1-Kpn1 insert of a commercially available pShuttle plasmid vector (Clontech). The construct No. used in Example 1 It was a construct constructed by inserting three enhancers (hTERT enhancer, SV40 enhancer and CMV enhancer) existing downstream of the expression gene of expression plasmid 14 (FIG. 20) in the form of BGH poly A + 3 enhancers. As a control, a vector constructed by inserting a DNA encoding human c-myc into the Xba1-Kpn1 insertion site of a commercially available pShuttle plasmid vector (Clontech) was used. 52 shows the base sequence of the inserted c-myc gene (SEQ ID NO: 29), and FIG. 14 shows the base sequence (SEQ ID NO: 30) of the region containing BGH poly A and three enhancers contained in No. 14.
Western blotting was performed using an anti-c-mycC antibody (Santa Cruz, Cat No .: sc-70469), and a cell extract 24 hours after transfection (total protein amount was 10 μg).
The results are shown in FIG. Lane 1 is the result of cell extract of cells transfected with a vector encoding REIC into a commercially available pShuttle vector. As a result, Lane 2 is inserted with a DNA encoding c-myc into a commercially available pShuttle vector, and three enhancers are added. -The result of the cell extract of the cell transfected with the expression vector inserted downstream of the DNA encoding myc (downstream of BGH poly A) is shown. As shown in the figure, an expression vector in which a DNA encoding c-myc is inserted into a commercially available pShuttle vector and three enhancers are inserted downstream of the DNA encoding c-myc (downstream of BGH poly A) is used. The strongest expression was observed. This result shows that the expression of the gene can be enhanced by incorporating the three enhancer parts of this system (construct backbone of construct No. 14) downstream of the expression gene cassette of a commercially available plasmid such as pShuttle vector. Indicates. That is, it is shown that it is possible to enhance the expression of the target gene by inserting three enhancer regions into various gene constructs. The result of this example is that the three enhancer parts of this system (construct skeleton of construct No. 14) are incorporated downstream of the expression gene cassette of the plasmid for expression of c-myc gene used for the production of iPS cells. , C-myc gene expression is enhanced. iPS cells are believed to be useful in various types of regenerative medicine, i.e., the enhancer moiety can be used as a means to enable stronger gene expression of so-called reprogramming genes such as c-myc, and the expressed protein itself. As a means for use in vivo or ex vivo as a regenerative factor, it is useful for regenerative medicine and the like.

Expression enhancement when hTERT is used as a promoter The expression cassette of the present invention containing GFP (Green fluorescein protein) as a foreign gene (inserted gene) was prepared, HEK293 cells were transfected, and the expressed protein was analyzed by Western blot . Transfections were performed using FuGENE ™ -HD, and GFP in the cell culture was detected by Western blotting after 24 hours.
The construct of the expression cassette used was the construct No. used in Example 1. 2 (FIG. 8) and construct no. 18, 19, 20 and 21. Construct No. The structures of 18, 19, 20 and 21 are shown in FIGS. 55, 56, 57 and 58, respectively. Construct No. 18 is a general gene expression vector containing the hTERT promoter. It is used in an environment where hTERT is highly expressed, that is, advantageous for strong gene expression in cancer cells, and is expected to express cancer cell-specific gene expression. However, the extremely weak gene expression has hindered clinical application to gene therapy and protein (medicine) production in specific cells. Construct No. 19 is a plasmid in which the RU5 sequence is inserted upstream of the expression gene of a general gene expression vector (construct No. 18) containing the hTERT promoter. Construct No. 20 is a plasmid in which an hTERT enhancer sequence is inserted downstream of the BGH poly A sequence of a general gene expression vector (construct No. 18) containing an hTERT promoter. Construct No. 21 is a plasmid in which an RU5 ′ sequence is inserted upstream of an expression gene of a general gene expression vector (construct No. 18) containing an hTERT promoter, and an hTERT enhancer sequence is further inserted downstream of a BGH poly A sequence. . In FIGS. 59-1 and 59-2 (continuation of FIG. The entire base sequence of 21 expression vectors is shown (SEQ ID NO: 31). In the base sequences of FIGS. 59-1 and 59-2, the portions surrounded by the frames (1), (2), (3), (4) and (5) are the hTERT core promoter and the minimal CMV promoter ( (Minimal CMV promoter), RU5 ′, GFP gene, BGH poly A, hTERT core promoter.
The result of expression is shown in FIG. As a result of the cell extract of the cells in which lane 1 does not express foreign protein, lanes 2 to 6 are the construct Nos. 2, no. 18, no. 19, no. 20 and no. The result made to express using 21 is shown. As shown in FIG. 18, no. 19, no. 20, no. 21 and no. Strong expression was observed in the order of 2. The result of this example is that this system (the form of the construct in which the target expression gene is sandwiched between a promoter and an enhancer) is a promoter of a gene weakly capable of gene expression, such as the hTERT promoter that enables cancer-specific gene expression. , Which are useful for significantly enhancing gene expression.

Expression construct No. when co-transfecting multiple expression vectors incorporating different foreign genes 2 (FIG. 20), a plasmid having a DNA encoding DsRed (red fluorescent protein), construct No. 21 (FIG. 58), a plasmid in which DNA encoding Yeast GST (Gratathione S transferase) is incorporated, construct No. Plasmids incorporating DNA encoding GFP into 21 (FIG. 58) were simultaneously transfected into cells and the expressed proteins were analyzed by Western blot. Transfections were performed using FuGENE ™ -HD. HEK293 cells, Hela cells, PC3 cells, HepG2 cells, HCT116 cells, MCF7 cell cancer cell lines are used, and OUMS-24 cells, which are human-derived fibroblasts, and human-derived keratinocyte cells as normal cell lines NHK cells were used. Each protein in the cell extract was detected by Western blotting 48 hours after transfection. DNA encoding DsRed and DNA encoding Yeast GST were prepared by artificial synthesis based on a known cDNA sequence.
Western blotting is performed using an anti-GFP antibody, an anti-6His antibody (MBL, used for detection of Telomerase added with 6His), an anti-tubulin antibody (Sigma), an anti-DsRed antibody (Clontech) and an anti-Yeast GST antibody. The cell extract 24 hours after transfection (total protein amount: 10 μg) was used.
The results are shown in FIG. As shown in FIG. 61, the plasmid construct (construct No. 21) containing the hTERT promoter is useful for gene expression specific to only cancer cells in various cancer cells and normal cells. That is, in this case, the gene is strongly expressed only in cancer cells, and gene expression in normal cells can be suppressed. In this regard, for example, in a plasmid construct (construct No. 2) containing a CMV promoter, gene expression is observed in both human cancer cells and normal cells, and gene expression specific to cancer cells cannot be achieved. A plasmid containing the hTERT promoter is useful in that gene expression can be achieved specifically in cancer cells.

Examination of production amount of human erythropoietin (Human EPO) by HEK293 cells (Human embryonic kidney cell) transfected with an expression vector containing the gene expression cassette of the present invention Add His tag to the C-terminal side for secretion expression of human erythropoietin The DNA fragment of the prepared EPO-His tag was constructed. A vector containing 14 constructs (referred to as SGE (Super Gene Expression) vector) and a pTracer (registered trademark) -EF vector (EF-1α promoter, Invitrogen) as a control were respectively incorporated.
As a host cell for secretory expression of human erythropoietin, 30 mL of a human kidney-derived cell in the logarithmic growth phase: FreeStyle 293-F cells (Invitrogen) is seeded in a 125 mL flask at a concentration of 5-6 × 10 ⁵ cells / mL, The culture was shaken overnight (125 rpm) using Freestyle 293 Expression 1 Media (Invitrogen) at 37 ° C. in the presence of 8% CO ₂ . The next day, 30 μg of SGE-EPO-His tag and pTracer (registered trademark) -EF-EPO-His were adjusted to a concentration of 1 × 10 ⁶ cells / mL and 293-F cells seeded in 30 mL in a 125 mL flask. The tag plasmid DNA was mixed with a gene introduction reagent: 293 Fectin (Invitrogen) for gene introduction. For 4 days after the transfection, the cells were cultured with shaking in the presence of 8% CO ₂ at 37 ° C., and the culture supernatant was collected. 18 μL of this culture supernatant was separated using SDS-PAGE, and a glycosylated EPO protein having a molecular weight of about 35 kDa was detected by CBB staining (FIG. 62).
Human erythropoietin protein secreted in 25 mL of culture supernatant collected after 4 days to estimate EPO production was purified using histidine affinity column chromatography (TALON-Affinity Resin (Clontech)), and the eluate was purified. It isolate | separated using SDS-PAGE and the purity of EPO protein was confirmed by CBB dyeing | staining (FIG. 63). Furthermore, the protein amount of this purified EPO protein was quantified by the Bradford method, and the protein amount obtained during 1 L culture was calculated from the purified protein amount during 25 mL culture (FIGS. 64A and B). As a result, human erythropoietin can produce about 8 times the amount of protein using the SGE vector as compared to the expression level in the pTracer (registered trademark) -EF vector. An extremely high expression level was achieved.

Examination of production amount of human REIC (Reduced Expression in Immortalized Cells) protein by HEK293 cells (Human embryonic kidney cell) transfected with an expression vector containing the gene expression cassette of the present invention According to the method described in Example 1, F cells were adjusted to a concentration of 1 × 10 ⁶ cells / mL and 180 mL seeded flasks were prepared for three 500 mL flasks, and 180 μg of REIC expression SGE vector (a vector containing the construct No. 14 construct) was added to each flask. Was transiently transfected using a gene introduction reagent: 293 Fectin (Invitrogen). For 4 days after the transfection, the cells were cultured with shaking in the presence of 8% CO ₂ at 37 ° C., and the culture supernatant was collected. 18 μL of this culture supernatant was separated using SDS-PAGE, and a glycosylated REIC protein having a molecular weight of about 55 kDa was detected by CBB staining (FIG. 65).
The collected culture supernatant is concentrated from 520 mL to 35 mL by ultrafiltration, the solvent is replaced with 20 mM Hepes Buffer (pH 7.2) using Sephadex ™ G25M column chromatography (GE Healthcare), and the REIC protein The containing fraction was collected. Thereafter, the protein was adsorbed using anion exchange column chromatography (DEAE-Toyopearl (registered trademark) 650M, Tosoh), and then a linear concentration gradient of sodium chloride (0) in 20 mM Hepes Buffer (pH 7.2). The peak fraction of REIC protein was confirmed under the condition that the sodium chloride concentration was about 0.35M. Each peak fraction was analyzed by SDS-PAGE, and a fraction composed only of high-purity REIC protein was recovered (FIG. 66). The amount of protein of this purified REIC protein was calculated from the absorbance (280 nm), and further converted from the amount of purified protein during 520 mL culture to calculate the amount of protein obtained during 1 L culture (FIG. 67). As a result, about 50 mg of purified protein with high purity could be obtained from the culture supernatant transfected with the REIC expression SGE vector. That is, it was proved that about 100 mg of a large amount of purified protein could actually be recovered when converted to 1 L of culture solution.

Expression of a gene comprising a DNA construct comprising a gene to be expressed and a poly A addition sequence downstream of the first promoter of the present invention, and further comprising an enhancer or a second promoter linked downstream of the DNA construct Cassettes for mass production are achieved by ultra-high expression of the target protein to be expressed by gene expression regardless of cell type, gene type or transfection reagent type. In addition to application as a reagent, a wide range of applications are possible for application as a therapeutic protein drug and for treatment, examination, and diagnosis using clinical genes. For example, (1) functional analysis of unknown genes that could not be conventionally analyzed in specific cells and tissues, (2) improvement of therapeutic effect by loading not only viruses but also non-viral vectors in gene therapy, (3) antibodies As a method for producing biopharmaceuticals such as pharmaceuticals in recent years, production of supercells that produce large amounts of specific human functional proteins in human cells, (4) efficient and inexpensive production of reagents and diagnostic agents used in various assays and clinical diagnostics It can bring about revolutionary evolution in the field of biotechnology, including application to law.
The DNA cassette for expression of the present invention can be widely applied not only as a reagent in the field of biotechnology but also for treatment, testing and diagnosis using genes in clinical practice.

SEQ ID NOs: 1-16, 19-31 Synthesis [Sequence Listing]

Claims (24)

(i) a DNA construct in which a first promoter, a gene to be expressed, and a poly A addition sequence are linked in this order; (ii) an enhancer or an enhancer in which UAS is linked upstream, at least the base of SEQ ID NO: 16 An enhancer comprising the hTERT enhancer consisting of the nucleotide sequence from the 2859th c to 3047th t of the sequence , in the order of (i) and (ii), with the enhancer immediately downstream of the poly A addition sequence or the UAS upstream A cassette for gene expression that can enhance protein expression of a gene linked to a linked enhancer. (i) a DNA construct in which a first promoter, a gene to be expressed, and a polyA addition sequence are linked in this order; (ii) an enhancer or an enhancer in which UAS is linked upstream, and at least the nucleotide sequence of SEQ ID NO: 16 The enhancer comprising the hTERT enhancer consisting of the nucleotide sequence from the 2859th c to 3047th t of (i) and (ii) in this order, and the enhancer or UAS linked upstream of the poly A addition sequence The gene expression cassette according to claim 1, wherein said enhancer is ligated (excluding those having an enhancer upstream of the first promoter).   The expression cassette according to claim 1 or 2, which has a structure in which a gene to be expressed is sandwiched between a first promoter and an enhancer without having any other gene expression mechanism downstream of the linked enhancer.   The expression cassette according to any one of claims 1 to 3, wherein the promoter is a promoter selected from the group consisting of CMV promoter, CMVi promoter, SV40 promoter, hTERT promoter, β-actin promoter and CAG promoter.   The expression cassette according to any one of claims 1 to 4, wherein the enhancer linked downstream of the poly A addition sequence further comprises a CMV enhancer and / or an SV40 enhancer. The enhancer linked downstream of the poly A addition sequence is an enhancer linked in this order to the hTERT enhancer, SV40 enhancer and CMV enhancer consisting of the nucleotide sequence from the 2859th c to 3047th t of the nucleotide sequence of SEQ ID NO: 16. The expression cassette according to any one of claims 1 to 5. The expression according to any one of claims 1 to 4, wherein the promoter is an hTERT promoter, and the enhancer is an hTERT enhancer comprising a nucleotide sequence from the 2859th c to 3047th t of the nucleotide sequence of SEQ ID NO: 16. Cassette. The promoter is a CMV promoter or a CMV i promoter, and the enhancer is an hTERT enhancer consisting of a base sequence from the 2859th c to 3047th t of the base sequence of SEQ ID NO: 16. 2. An expression cassette according to 1. The expression cassette according to any one of claims 1 to 8, further comprising at least one of the following elements (i) and (ii):
(i) RU5 'linked immediately upstream of the gene to be expressed; and
(ii) SV40-ori linked to the uppermost stream of the expression cassette.   The DNA encoding a protein to be expressed is a therapeutic gene that can be used for treatment of a disease, or a DNA that encodes a protein that can be used for a medicine, a diagnostic agent, or a reagent. The cassette for expression as described.   The expression cassette according to claim 10, wherein the therapeutic gene is a REIC / Dkk-3 gene which is a tumor suppressor gene that can be used for treatment of a tumor. The cassette for gene expression according to claim 6, which has a structure of a construct selected from the group consisting of construct No. 14, construct No. 16, and construct No. 17 having the structure shown below.

,

,as well as
  A vector comprising the gene expression cassette according to any one of claims 1 to 12.   The vector according to claim 13, which is an adenovirus or an adeno-associated virus vector.   A host cell comprising the vector according to claim 13 or 14.   A preparation for disease detection or treatment comprising the vector according to claim 13 or 14.   A method for expressing a gene to be expressed using the expression cassette according to any one of claims 1 to 12 or the vector according to claim 13 or 14.   A gene to be expressed, which comprises introducing the expression cassette according to any one of claims 1 to 12 or the vector according to claim 13 or 14 into a cell and culturing the cell, is encoded. A method for producing a protein. In the expression cassette for the expression of the first promoter, the gene to be expressed, the poly A addition sequence and the gene containing the enhancer, the first promoter, the gene to be expressed and the poly A addition sequence are arranged in this order. Enhancer immediately downstream of the poly A addition sequence of the DNA construct ligated with or UAS linked upstream of UAS, and consists of at least the 2859th c to 3047th t of the nucleotide sequence of SEQ ID NO: 16 A method of enhancing protein expression of a gene by linking enhancers including hTERT enhancers. In the expression cassette for the expression of the first promoter, the gene to be expressed, the poly A addition sequence and the gene containing the enhancer, the first promoter, the gene to be expressed and the poly A addition sequence are arranged in this order. Enhancer immediately downstream of the poly A addition sequence of the DNA construct ligated with or UAS linked upstream of UAS, and consists of at least the 2859th c to 3047th t of the nucleotide sequence of SEQ ID NO: 16 20. The method according to claim 19, wherein the protein expression of the gene is enhanced by linking an enhancer including an hTERT enhancer (except when an enhancer is linked upstream of the first promoter).   21. The method of claim 19 or 20, wherein the enhancer linked downstream of the poly A addition sequence further comprises a CMV enhancer and / or an SV40 enhancer. The enhancer linked downstream of the poly A addition sequence is an enhancer linked in this order to the hTERT enhancer, SV40 enhancer and CMV enhancer consisting of the nucleotide sequence from the 2859th c to 3047th t of the nucleotide sequence of SEQ ID NO: 16. The method according to any one of claims 19 to 21, wherein: 21. The method according to claim 19 or 20, wherein the promoter is an hTERT promoter, and the enhancer is an hTERT enhancer comprising a nucleotide sequence from the 2859th c to the 3047th t of the nucleotide sequence of SEQ ID NO: 16 . The method according to claim 19 or 20, wherein the promoter is a CMV promoter or a CMVi promoter, and the enhancer is an hTERT enhancer consisting of a nucleotide sequence from the 2859th c to 3047th t of the nucleotide sequence of SEQ ID NO: 16 .